sys_un.h(0P) POSIX Programmer's Manual sys_un.h(0P)PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the corresponding
Linux manual page for details of Linux behavior), or the interface may
not be implemented on Linux.
NAME
sys/un.h — definitions for UNIX domain sockets
SYNOPSIS
#include <sys/un.h>
DESCRIPTION
The <sys/un.h> header shall define the sockaddr_un structure, which
shall include at least the following members:
sa_family_t sun_family Address family.
char sun_path[] Socket pathname.
The sockaddr_un structure is used to store addresses for UNIX domain
sockets. Pointers to this type shall be cast by applications to struct
sockaddr * for use with socket functions.
The <sys/un.h> header shall define the sa_family_t type as described in
<sys/socket.h>.
The following sections are informative.
APPLICATION USAGE
The size of sun_path has intentionally been left undefined. This is
because different implementations use different sizes. For example, 4.3
BSD uses a size of 108, and 4.4 BSD uses a size of 104. Since most
implementations originate from BSD versions, the size is typically in
the range 92 to 108.
Applications should not assume a particular length for sun_path or
assume that it can hold {_POSIX_PATH_MAX} bytes (256).
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
<sys_socket.h>
The System Interfaces volume of POSIX.1‐2008, bind(), socket(), socket‐
pair()COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
cal and Electronics Engineers, Inc and The Open Group. (This is
POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online
at http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the source
files to man page format. To report such errors, see https://www.ker‐
nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 sys_un.h(0P)
